In power transmission networks alternating current (AC) power is typically converted to direct current (DC) power for transmission via overhead lines and/or under-sea cables. This conversion removes the need to compensate for the AC capacitive load effects imposed by the transmission line or cable and reduces the cost per kilometre of the lines and/or cables, and thus becomes cost-effective when power needs to be transmitted over a long distance.
HVDC converters are used to convert between AC power and DC power and such converters are one example of an electrical equipment item that incorporates a number of high voltage assemblies, i.e. electrical assemblies which typically operate at or above about 1.5 kV DC, that are capable of storing a charge.